A High-Resolution Map of Singapore’s Terrestrial Ecosystems

Abstract

The natural and semi-natural areas within cities provide important refuges for biodiversity, as well as many benefits to people. To study urban ecology and quantify the benefits of urban ecosystems, we need to understand the spatial extent and configuration of different types of vegetated cover within a city. It is challenging to map urban ecosystems because they are typically small and highly fragmented; thus requiring high resolution satellite images. This article describes a new high-resolution map of land cover for the tropical city-state of Singapore. We used images from WorldView and QuickBird satellites, and classified these images using random forest machine learning and supplementary datasets into 12 terrestrial land classes. Close to 50 % of Singapore’s land cover is vegetated while freshwater fills about 6 %, and the rest is bare or built up. The overall accuracy of the map was 79 % and the class-specific errors are described in detail. Tropical regions such as Singapore have a lot of cloud cover year-round, complicating the process of mapping using satellite imagery. The land cover map provided here will have applications for urban biodiversity studies, ecosystem service quantification, and natural capital assessment.

Factors influencing nature interactions vary between cities and types of nature interactions

“…The distribution of urban greenspace across (a) Singapore (adapted from Gaw et al., 2019) and (b) Brisbane (adapted from Caynes et al., 2016); and the predominant housing type in (c) Singapore and (d) Brisbane (extracted from Google Street View)…”

“…The distribution of urban greenspace across (a) Singapore (adapted fromGaw et al, 2019) and (b) Brisbane (adapted from Caynes et al, 2016); and the predominant housing type in (c) Singapore and (d) Brisbane (extracted from Google Street View) This suggests that older people in Brisbane spent more time on intentional interactions in gardens (but less time for all other types of nature interactions;…”

Development of spontaneous vegetation on reclaimed land in Singapore measured by NDVI

“…The classes that represented ‘Newly reclaimed land’ were then used as a mask to extract NDVI values within the reclaimed areas in each year [ 43 ]. Five sites of reclaimed land were selected for further analysis, as these sites are known to contain mainly spontaneous vegetation rather than intentionally planted park spaces [ 23 ]. They are Tuas, Jurong, Semakau, Changi, and Tekong.…”

No evidence of an extinction of experience or emotional disconnect from nature in urban Singapore

“…The red boundary delineates the residential district of Clementi. More detailed views of Clementi, along with the locations of the four bird transects are shown on (b) a topographic map from 1996 at 1:50,000 scale, obtained from the Urban Redevelopment Authority of Singapore and (c) an adapted landcover map from Gaw, Yee, and Richards (2019) using Worldview and QuickBird satellite imagery from 2018…”